Well, in the fanfiction world, it could be that Peter has been exposed to some sort of strange magic or potion. Maybe he's been in a fight with a powerful villain and received some sort of invisible injury that's affecting him internally.
Some characters could offer emotional support. They could stay by Peter's side, talk to him, and encourage him. This might not directly solve the physical problem, but it could boost his mental state, which in turn could help his body fight off whatever is making him feel unwell. Also, they could provide him with resources like food or a safe place to rest if that's relevant in the fanfiction.
One reason could be his own clumsiness. Maybe Peter is always in a rush and not paying enough attention to his surroundings. For example, he could be running down the stairs while looking at his phone and trip, resulting in an injury.
Well, one reason could be that he's on a secret mission for S.H.I.E.L.D. that requires him to go undercover and cut off all contact. Maybe he's investigating a new super - villain threat that's too dangerous to let anyone know about.
It could also be due to external pressure. The media or some powerful figures in the fanfiction world might force Tony to stay away from Peter. They could spread false rumors about their relationship or use their influence to separate them for their own gain.
Maybe Peter has some urgent news to share. For example, he might have discovered a new threat to the city or a problem related to one of their projects. He could also be in trouble himself and needs Tony's immediate help.
Maybe the character is afraid of what lies ahead. It could be a new and unknown situation, like a dangerous mission or an unfamiliar place. For example, if it's a superhero fanfiction, the character might not be fully trained yet and is worried about getting hurt or failing.
One possible reason could be getting lost in a dangerous and unfamiliar place, like a thick forest or a maze - like old building. Maybe there are no clear paths or signs to guide the way back.
Maybe it's due to a new and powerful enemy's attack. In fanfiction, authors might create unique villains with abilities that specifically target Peter's weaknesses. For example, if the villain has the power to disrupt Spider - Man's enhanced senses, it could cause Peter to be disoriented and ultimately collapse. Another aspect could be that Peter overuses his powers without proper rest, which exhausts his body and causes him to collapse.
In the fanfiction, Maryjane could be in love with someone else at the time. Even if she has some feelings for Peter, her stronger feelings for another person make her reject Peter. Also, Peter might have done something in the past that Maryjane can't forgive, like lying to her, which results in the rejection.
It could be a result of a genetic mutation that is unique to the fanfiction world he is in. This mutation might be triggered by extreme stress or exposure to certain substances, causing his eyes to bleed. For example, if he has been in an area filled with some strange radioactive - like substances that affect his body in this unusual way.